The big theme out of Tuesday night's Republican presidential debate in Washington was Newt Gingrich's compassionate stance toward illegal immigrants who have put down deep roots in the U.S.

That position by Gingrich, who has recently surged to join Mitt Romney at the head of the Republican field according to recent polls, conflicted with the more hardline views of many conservative voters.

Many of those GOP voters who will decide their party's nominee oppose allowing illegal immigrants to remain in the U.S., period.

The immediate question for Gingrich was, after boldly defending his position that undocumented immigrants who've lived in the U.S. for many years, establishing families and belonging to churches, should be allowed to remain in the U.S., would Gingrich now suffer the same fate as Texas Gov. Rick Perry.

While a number of Perry stumbles led to his fall from the front to rear of the GOP pack, the start of his decline was his defense of his relatively moderate immigration position.

Romney's attacks on the Texas governor's support for in-state tuition for undocumented immigrants, for instance, helped to stop Perry's initial momentum and the former frontrunner has never recovered.

As aware as Gingrich was of this recent history, the former House speaker didn't retreat even when Romney said Gingrich's position amounted to a "magnet" while another rival, Rep. Michele Bachmann of Minnesota, referred to it as an amnesty. Gingrich said:

"If you've been here 25 years and you got three kids and two grandkids, you've been paying taxes and obeying the law, you belong to a local church, I don't think we're going to separate you from your family, uproot you forcefully and kick you out."

As he did weeks ago to Perry for a moderate immigration stance, Romney went after Gingrich. Romney said:

"There's — there's no question. But to — saying that we're going to say to the people who've come here illegally that now you're all going to get to stay, or some large number are going to get to stay and become permanent residents of the United States, that will only encourage more people to do the same thing. People respond to incentives. And if you could become a permanent resident of the United States by coming here illegally, you'll do so. What I want to do is bring people into this country legally, particularly those that have education and skill that allows us to compete globally. "

It remains to be seen if Romney's attacks and the antipathy of many conservatives to "amnesty" spell doom for Gingrich's bid as they seemed to for Perry. Gingrich may be able to better weather the coming storm because he possesses vastly superior rhetorical skills than Perry.

In terms of the overall shape of the race, the debate did little to knock Romney from his perch as the likely nominee. Even though there was some Romney weirdness during the opening introductions when the former Massachusetts governor said Mitt was his real first name when it's actually Willard, that didn't seem like a big enough gaffe to derail him. .

Aside from that, however, Romney, as usual, cruised comfortably through the debate, rattling off facts with aplomb and still seeming like the candidate who could best measure up on the same stage against President Obama.

Jon Huntsman had one of his better debates, no doubt because the topics of foreign policy and national security played to his strength as a former U.S. ambassador to China.

Rep. Ron Paul of Texas again provided some of the most memorable moments of a presidential debate by offering the usual libertarian contrasts to the GOP orthodoxy, opposing U.S. troops in Iraq and the Patriot Act for instance as his rivals looked on with amusement or exasperation.

Herman Cain, the former pizza company CEO, and former frontrunner did nothing to redeem himself following his painful flub of the Libya question when he met with journalists last week in Milwaukee.

Bachmann beat Perry when the debate turned to Pakistan which wasn't hard since Perry seemed tentative and Bachmann well briefed, as one might expect for a member of the House Intelligence Committee.

But it amounted to kicking a man when he was down, a performance unlikely to resurrect her candidacy.

Meanwhile, Rick Santorum, the former U.S. senator from Pennsylvania was left still looking for his breakout. Others were left wondering just how much longer he would hang in the race.

The debate, shown on CNN and held at the historic DAR Constitution Hall, was sponsored by the conservative think tanks the American Enterprise Institute and the Heritage Foundation.

That fact led to a procession of George W. Bush era neocons in the audience who posed questions to the candidates. They included Paul Wolfowitz, who served as a top Defense Department official when Donald Rumsfeld was Defense Secretary and David Addington who was chief of staff to Vice President Dick Cheney.

The night began with even more of a blast-from-the-past than that. Ed Meese, who served as President Ronald Reagan's attorney general, got to throw out the first question.